1. Technical Field
Example embodiments of the present invention relate to a software-defined networking (SDN) technology, and more specifically to methods for managing transactions in a software defined network.
2. Related Art
The networks comprising conventional routers and switches are configured with complex protocols and functions. Since operation methods and user interfaces for them are different according to vendors of apparatuses, it is difficult for network operators and researchers on network technologies to develop new network protocols to be applied to networks, to expand the network, and to make the network apparatuses interwork with each other. In order to overcome the above-described problem, there have been studies on technologies of switches and routers having open-type interface. However, since the network technologies based on the open-type interfaces are expensive as compared with their performances, their commercialization was not achieved easily.
‘OpenFlow’ technology appeared in order to resolve the high cost problem, and provide users and developers with open-type standardized interfaces.
The OpenFlow technology separates a packet forwarding function and a control function of a network switch, and provides a standardized protocol for communicating between the two functions. Therefore, if the OpenFlow technology is used, packet paths may be determined by using software driven in an external control apparatus, and traffic may be controlled more precisely than the conventional technologies.
Open Networking Foundation (ONF) has defined a software defined networking (hereinafter, referred to as ‘SDN’) technology which can enable easier network programming possible based on OpenFlow.
A SDN structure based on OpenFlow comprises a plurality of OpenFlow switches and at least one controller. The OpenFlow switches and the controller may be connected to each other by using the OpenFlow protocol.
In the SDN network based on OpenFlow, a controller may provide flow table information to switches, and the switches may change properties of packets using the provided flow table information, or process the packets by controlling flows of the packets.
Meanwhile, in addition to the ONF, various standardization organizations such as an Internet Engineering Task Force (IETF), a European Telecommunication Standards Institute (ETSI), an International Telecommunications Union-Telecommunication (ITU-T), etc. have been progressing standardization on the SDN-based networks. For example, an Interface to the Routing System (I2RS) working group of IETF is progressing standardization for open-type interface structures located between an external client and an agent located in a router, which can make it possible that conventional router apparatuses can be monitored and controlled by the external controller.
As described above, although various standard organizations such as the ONF and the IETF have been progressing the standardization on the SDN technology, a detail method for guaranteeing consistency of transactions between a controller and at least one switch, or between a client and at least one agent has not been proposed yet.